The Library of Congress maintains a large collection of retrospective foreign and domestic telephone directories, although most of these are not cataloged. (More specialized directories for commerce, industry and specific professions are indeed cataloged and may be identified in the Library's online catalog.)

The uncataloged directories listed in this guide reflect holdings of Latvian telephone directories prior to the year 2000.

As Russian was mandatory for many publications during Soviet rule, some of the directories are in Russian, and some even have the Latvian names written with Cyrillic letters. Each entry on the list specifies the language in which the book was printed, and the alphabet that was used for people's names. The newer directories are in standard Latvian, employing Roman letters.

Apart from telephone books which list phone numbers for all of Latvia, the Library of Congress also has specialized directories, some for example that list information for the members, staff and offices of the Latvian Academy of Sciences.